I would like to add one more phenomenon to the "compatible material" potential problem… "Galling"…
This is why "unlike" materials are used, where rubbing is likely.
Below is a picture of the early generation primary quick release, used by a few manufacturers. A lot can be said about the pros and cons of this "slide-bolt" type of release. Here is a 'bonus' question for you old-timers: "What was the major short-coming of this style release?"
One of the good design features of this type of release was the use of "fabric" webbing tubes for the stainless steel pin to slide through. The use of stainless steel tubes presented problems with "galling" and type one or two pitting corrosion, along with abrasion from trapped sand particles. A metallurgist could go on and on about this kind of compatibility problem. I have gone on long enough…
Below is a picture of the old "slide-bolt" release, right next to an invention prototype, where the "slide-bolt" mechanism was located inside the bar itself… and was used to quick disconnect the end of the slider rope, in an emergency, in the case of a primary release malfunction. This is just another example of how a device could be hidden inside a spreader bar... food for thought...
"Galling is a form of wear caused by adhesion between sliding surfaces. When a material galls, some of it is pulled with the contacting surface, especially if there is a large amount of force compressing the surfaces together. Galling is caused by a combination of friction and adhesion between the surfaces, followed by slipping and tearing of crystal structure beneath the surface. This will generally leave some material stuck or even friction welded to the adjacent surface, while the galled material may appear gouged with balled-up or torn lumps of material stuck to its surface.
Galling is most commonly found in metal surfaces that are in sliding contact with each other. It is especially common where there is inadequate lubrication between the surfaces. However, certain metals will generally be more prone to galling, due to the atomic structure of their crystals. For example, aluminum is a metal which will gall very easily, whereas annealed (softened) steel is slightly more resistant to galling. Steel that is fully hardened is very resistant to galling.
Galling is a common problem in most applications where metals slide while in contact with other metals. This can happen regardless of whether the metals are the same or of different kinds. Metals such as brass are often chosen for bearings, bushings, and other sliding applications because of their resistance to galling, as well as other forms of mechanical abrasion"……Wikipedia reference.
